Emerging Biomarkers in Cardiac Sarcoidosis and Other Inflammatory Cardiomyopathies

PURPOSE OF REVIEW

Cardiac sarcoidosis and other inflammatory cardiomyopathies are disorders causing cardiac inflammation and leading to heart failure, arrythmias and cardiac arrest. Diagnosis of these entities remains challenging and multimodal. Thus, there is a growing need to develop reliable biomarkers that can aid in the diagnosis. This review aims to summarize and highlight recent findings in the field of biomarkers for cardiac sarcoidosis and inflammatory cardiomyopathy.

RECENT FINDINGS

Multiple categories of biomarkers including novel molecules are being investigated with the latest evidence showing promising results. Some of these biomarkers are proven to be useful as diagnostic and prognostic aids in cardiac sarcoid and inflammatory cardiomyopathy. The identification of cost-effective and accurate biomarkers is useful not only for enhancing diagnostic accuracy but also for informing therapeutic decision-making processes. This advancement would facilitate the timely institution of immunosuppressive therapies, ultimately leading to improved patient outcomes.

Cardiovascular adaptations and pathological changes induced by spaceflight: from cellular mechanisms to organ-level impacts

The advancement in extraterrestrial exploration has highlighted the crucial need for studying how the human cardiovascular system adapts to space conditions. Human development occurs under the influence of gravity, shielded from space radiation by Earth's magnetic field, and within an environment characterized by 24-hour day-night cycles resulting from Earth's rotation, thus deviating from these conditions necessitates adaptive responses for survival. With upcoming manned lunar and Martian missions approaching rapidly, it is essential to understand the impact of various stressors induced by outer-space environments on cardiovascular health. This comprehensive review integrates insights from both actual space missions and simulated experiments on Earth, to analyze how microgravity, space radiation, and disrupted circadian affect cardiovascular well-being. Prolonged exposure to microgravity induces myocardial atrophy and endothelial dysfunction, which may be exacerbated by space radiation. Mitochondrial dysfunction and oxidative stress emerge as key underlying mechanisms along with disturbances in ion channel perturbations, cytoskeletal damage, and myofibril changes. Disruptions in circadian rhythms caused by factors such as microgravity, light exposure, and irregular work schedules, could further exacerbate cardiovascular issues. However, current research tends to predominantly focus on disruptions in the core clock gene, overlooking the multifactorial nature of circadian rhythm disturbances in space. Future space missions should prioritize targeted prevention strategies and early detection methods for identifying cardiovascular risks, to preserve astronaut health and ensure mission success.

Efficacy and safety of the urate-lowering agent febuxostat in chronic heart failure patients with hyperuricemia: results from the LEAF-CHF study

Hyperuricemia is an independent predictor of mortality in patients with chronic heart failure (CHF). To determine whether febuxostat, a urate-lowering agent, may improve clinical outcomes in CHF patients, we conducted a multicenter, prospective, randomized, open-label, blinded endpoint study with a treatment period of 24 weeks. We randomly assigned Japanese outpatients diagnosed with both CHF with reduced left ventricular ejection fraction (LVEF < 40%) and asymptomatic hyperuricemia (serum uric acid [UA] levels > 7.0 mg/dl and < 10.0 mg/dl) to either a febuxostat group (n = 51) or a control group (n = 50). The primary efficacy endpoint was the change in log-transformed plasma B-type natriuretic peptide (BNP) levels from baseline to week 24 (or at discontinuation). The secondary efficacy endpoints were the changes in LV systolic or diastolic function evaluated by echocardiography, New York Heart Association (NYHA) class, hemoglobin, and estimated glomerular filtration rate from baseline to week 24, and the change in log-transformed plasma BNP levels or serum UA levels from baseline to weeks 4, 8, 12, 16 and 20 (BNP) or weeks 4, 8, 12, 16, 20 and 24 (serum UA). The primary safety endpoints were occurrence of all-cause death or major cardiovascular events. The mean age of participants was 70 years; 14% were female. The febuxostat group and the control group did not differ with respect to the primary efficacy endpoint (p = 0.13), although the decrease in log-transformed plasma BNP levels from baseline to each of weeks 4, 8, 12, 16 and 20 was greater in the febuxostat group. There were no significant differences between the two groups in the primary safety endpoints or the secondary efficacy endpoints except reduced serum UA levels in the febuxostat group. Febuxostat did not reduce plasma BNP levels at week 24 in patients with CHF, but it appeared safe with no increase in major cardiovascular events and all-cause or cardiovascular mortality.

CypD induced ROS output promotes intracranial aneurysm formation and rupture by 8-OHdG/NLRP3/MMP9 pathway

Reactive Oxygen Species (ROS) are widely accepted as a pernicious factor in the progression of intracranial aneurysm (IA), which is eminently related to cell apoptosis and extracellular matrix degradation, but the mechanism remains to be elucidated. Recent evidence has identified that enhancement of Cyclophilin D (CypD) under stress conditions plays a critical role in ROS output, thus accelerating vascular destruction. However, no study has confirmed whether cypD is a detrimental mediator of cell apoptosis and extracellular matrix degradation in the setting of IA development. Our data indicated that endogenous cypD mRNA was significantly upregulated in human IA lesions and mouse IA wall, accompanied by higher level of ROS, MMPs and cell apoptosis. CypD-/- remarkably reversed vascular smooth muscle cells (VSMCs) apoptosis and elastic fiber degradation, and significantly decreased the incidence of aneurysm and ruptured aneurysm, together with the downregulation of ROS, 8-OHdG, NLRP3 and MMP9 in vivo and vitro. Furthermore, we demonstrated that blockade of cypD with CsA inhibited the above processes, thus preventing IA formation and rupture, these effects were highly dependent on ROS output. Mechanistically, we found that cypD directly interacts with ATP5B to promote ROS release in VSMCs, and 8-OHdG directly bind to NLRP3, which interacted with MMP9 to increased MMP9 level and activity in vivo and vitro. Our data expound an unexpected role of cypD in IA pathogenesis and an undescribed 8-OHdG/NLRP3/MMP9 pathway involved in accelerating VSMCs apoptosis and elastic fiber degradation. Repressing ROS output by CypD inhibition may be a promising therapeutic strategy for prevention IA development.

Novel Oxidative Stress Biomarkers with Risk Prognosis Values in Heart Failure

Oxidative stress (OS) is mediated by reactive oxygen species (ROS), which in cardiovascular and other disease states, damage DNA, lipids, proteins, other cellular and extra-cellular components. OS is both initiated by, and triggers inflammation, cardiomyocyte apoptosis, matrix remodeling, myocardial fibrosis, and neurohumoral activation. These have been linked to the development of heart failure (HF). Circulating biomarkers generated by OS offer potential utility in patient management and therapeutic targeting. Novel OS-related biomarkers such as NADPH oxidases (sNox2-dp, Nrf2), advanced glycation end-products (AGE), and myeloperoxidase (MPO), are signaling molecules reflecting pathobiological changes in HF. This review aims to evaluate current OS-related biomarkers and their associations with clinical outcomes and to highlight those with greatest promise in diagnosis, risk stratification and therapeutic targeting in HF.

Genome instability in peripheral blood lymphocytes of patients with heart failure and reduced ejection fraction

Heart failure (HF) is a complex clinical condition characterized by functional and structural defects of the myocardium, but genetic and environmental factors are considered to play an important role in the development of the disease. In the present study, we investigated the genome instability (DNA and chromosomal damage) in patients with heart failure with reduced ejection fraction (HFrEF) ≤40% and its association with risk factors. The studied population included 48 individuals, of which 29 HFrEF patients (mean age 57.41 ± 5.74 years) and 19 healthy controls (mean age 57.63 ± 6.09 years). The genetic damage index in peripheral blood lymphocytes was analyzed using the comet assay, while micronuclei frequency and nuclear division index were analyzed using the cytokinesis-block micronucleus assay. Our results showed that HFrEF patients had a significantly higher genetic damage index compared with the healthy controls (P < .001). Cytokinesis-block micronucleus assay showed that the average micronucleus frequency in peripheral blood lymphocytes of patients was significantly higher, while the nuclear division index values were significantly lower than in controls (P < .01). Using multiple linear regression analysis, pathological state, ejection fraction, creatinine, glucose, associated disease, residence, proBNP, troponin, urea, ACE-inhibitors, and length of the drug therapy were identified as predictors of DNA and/or chromosomal damage in HF patients. We can conclude that DNA and chromosomal damage was increased in patients with HF, which may be a consequence of disease and/or drug therapy.

Urinary 8-oxoGuo as a potential novel evaluation index for patients with nephrotic syndrome

Urinary 8-oxo-7,8-dihydroguanosine (8-oxoGuo) and 8-oxo-7,8-dihydro-2'- deoxyguanosine (8-oxodGuo) are considered biomarkers of oxidative stress, and patients with nephrotic syndrome have been reported to have increased oxidative stress levels. In this study, we aimed to assess the value of 8-oxoGuo and 8-oxodGuo as novel biomarkers to evaluate the severity of nephrotic syndrome. In total, 107 patients with nephrotic syndrome and 116 healthy controls were recruited for this study. The concentrations of urinary 8-oxoGuo and 8-oxodGuo were measured using isotope-labeled liquid chromatography with tandem mass spectrometry. Urinary creatinine was used to regulate 8-oxoGuo and 8-oxodGuo concentrations. Urinary 8-oxoGuo and 8-oxoGuo/Cr levels in patients with nephrotic syndrome were significantly higher than those in healthy control participants. 8-oxoGuo/Cr showed a positive correlation with the 24 h urinary total protein (UTP) and UTP levels and negative correlations with serum total protein and albumin levels. After treatment, urinary 8-oxoGuo and 8-oxoGuo/Cr levels were significantly lower in the group with a low 24 h-UTP value (<3.5 g/d) than in the high value group. 8-oxoGuo can be used as a feasible and reliable biomarker for the assessment of nephrotic syndrome.HighlightsUrinary 8-oxoGuo level was significantly increased in patients with nephrotic syndrome.Urinary 8-oxoGuo level increased with an increase in plasma protein and a decrease in urine protein.Urinary 8-oxoGuo level decreased with nephrotic syndrome remission when urinary microalbumin showed no significant change.Urinary 8-oxoGuo level can be used as novel biomarkers of nephrotic syndrome.

Modulation of Reactive Oxygen Species Homeostasis as a Pleiotropic Effect of Commonly Used Drugs

Age-associated diseases represent a growing burden for global health systems in our aging society. Consequently, we urgently need innovative strategies to counteract these pathological disturbances. Overwhelming generation of reactive oxygen species (ROS) is associated with age-related damage, leading to cellular dysfunction and, ultimately, diseases. However, low-dose ROS act as crucial signaling molecules and inducers of a vaccination-like response to boost antioxidant defense mechanisms, known as mitohormesis. Consequently, modulation of ROS homeostasis by nutrition, exercise, or pharmacological interventions is critical in aging. Numerous nutrients and approved drugs exhibit pleiotropic effects on ROS homeostasis. In the current review, we provide an overview of drugs affecting ROS generation and ROS detoxification and evaluate the potential of these effects to counteract the development and progression of age-related diseases. In case of inflammation-related dysfunctions, cardiovascular- and neurodegenerative diseases, it might be essential to strengthen antioxidant defense mechanisms in advance by low ROS level rises to boost the individual ROS defense mechanisms. In contrast, induction of overwhelming ROS production might be helpful to fight pathogens and kill cancer cells. While we outline the potential of ROS manipulation to counteract age-related dysfunction and diseases, we also raise the question about the proper intervention time and dosage.

Enhanced oxidative stress and presence of ventricular aneurysm for risk prediction in cardiac sarcoidosis

OBJECTIVE

Sudden cardiac death (SCD) is the major cause of death in cardiac sarcoidosis (CS). We aimed to identify the prognostic markers for sustained ventricular tachycardia (sVT) and SCD in patients with CS.

METHODS

We performed a prospective observational cohort study for patients with CS diagnosed according to the Japanese or Heart Rhythm Society guidelines between June 2008 and March 2020 in our hospital. The primary endpoint was a composite of the first sVT and SCD. The levels of urinary 8-hydroxy-2'-deoxyguanosine (U-8-OHdG), a marker of oxidative DNA damage that reflects the inflammatory activity of CS, other biomarkers, and indices of cardiac function and renal function were measured on admission.

RESULTS

Eighty-nine consecutive patients with CS were enrolled; 28 patients with no abnormal 18F-fluorodeoxyglucose (18F-FDG) accumulation in the heart were excluded and 61 patients with abnormal 18F-FDG accumulation were followed up for a median of 46 months (IQR: 20-84). During the follow-up period, 15 of 61 patients showed sVT (n=12) or SCD (n=3). A Cox proportional hazard model showed that U-8-OHdG concentration and presence of ventricular aneurysm (VA) were independent predictors of first sVT/SCD. The cut-off U-8-OHdG concentration for predicting first sVT/SCD was 14.9 ng/mg·Cr. Patients with U-8-OHdG concentration ≥14.9 ng/mg·Cr and VA showed a significantly increased risk of sVT/SCD.

CONCLUSIONS

U-8-OHdG and presence of VA were powerful predictors of first sVT/SCD in patients with CS, facilitating the stratification of cardiac events and providing relevant information about the substrates of ventricular tachycardia.

Impact of citrus fruit intake on the mental health of patients with chronic heart failure

BACKGROUND

The full impact of the intake of citrus fruits on the risk of depression in individuals with chronic heart failure (HF) is unknown. Here, we examined the associations between the estimated habitual intakes of citrus fruits and depressive symptoms in patients with chronic HF.

METHODS

We enrolled 150 stable outpatients with chronic HF who had a history of worsening HF. To assess the patients' daily dietary patterns, we used a brief self-administered diet-history questionnaire to calculate the daily consumption of foods and nutrients. To assess the patients' mental state, we used a nine-item Patient Health Questionnaire (PHQ-9).

RESULTS

Twelve patients (8%) were identified as having moderate-to-severe depression (PHQ-9 score ≥10). The patients with PHQ-9 ≥10 had lower daily intakes of citrus fruits compared to those with no or mild depressive symptoms (PHQ-9 <10). The daily intakes of various antioxidants, including vitamin C, β-carotene, and β-cryptoxanthin, all of which are abundant in citrus fruits, were reduced in the patients with PHQ-9 ≥10, accompanied by higher serum levels of 8-isoprostane (an oxidative stress marker). A multivariate logistic regression analysis using forward selection showed that a lowered daily intake of citrus fruits was an independent predictor of the comorbidity of moderate-to-severe depression in patients with chronic HF, after adjustment for age, gender, and the hemoglobin value.

CONCLUSIONS

A lower daily consumption of citrus fruits was associated with higher prevalence of depression in patients with chronic HF. Our findings support the hypothesis that a daily consumption of citrus fruits has a beneficial effect on the prevention and treatment of depression in chronic HF patients.

Antioxidant Approach as a Cardioprotective Strategy in Chemotherapy-Induced Cardiotoxicity

Significance: Chemotherapy-induced cardiotoxicity (CTX) has been associated with redox signaling imbalance. In fact, redox reactions are crucial for normal heart physiology, whereas excessive oxidative stress can cause cardiomyocyte structural damage. Recent Advances: An antioxidant approach as a cardioprotective strategy in this setting has shown encouraging results in preventing anticancer drug-induced CTX. Critical Issues: In fact, traditional heart failure drugs as well as many other compounds and nonpharmacological strategies, with a partial effect in reducing oxidative stress, have been shown to counterbalance chemotherapy-induced CTX in this setting to some extent. Future Directions: Given the various pathways of toxicity involved in different chemotherapeutic schemes, interactions with redox balance need to be fine-tuned and a personalized cardioprotective approach seems to be required.

Systemic oxidative stress is associated with lower aerobic capacity and impaired skeletal muscle energy metabolism in heart failure patients

Oxidative stress plays a role in the progression of chronic heart failure (CHF). We investigated whether systemic oxidative stress is linked to exercise intolerance and skeletal muscle abnormalities in patients with CHF. We recruited 30 males: 17 CHF patients, 13 healthy controls. All participants underwent blood testing, cardiopulmonary exercise testing, and magnetic resonance spectroscopy (MRS). The serum thiobarbituric acid reactive substances (TBARS; lipid peroxides) were significantly higher (5.1 ± 1.1 vs. 3.4 ± 0.7 μmol/L, p < 0.01) and the serum activities of superoxide dismutase (SOD), an antioxidant, were significantly lower (9.2 ± 7.1 vs. 29.4 ± 9.7 units/L, p < 0.01) in the CHF cohort versus the controls. The oxygen uptake (VO₂) at both peak exercise and anaerobic threshold was significantly depressed in the CHF patients; the parameters of aerobic capacity were inversely correlated with serum TBARS and positively correlated with serum SOD activity. The phosphocreatine loss during plantar-flexion exercise and intramyocellular lipid content in the participants' leg muscle measured by ³¹phosphorus- and ¹proton-MRS, respectively, were significantly elevated in the CHF patients, indicating abnormal intramuscular energy metabolism. Notably, the skeletal muscle abnormalities were related to the enhanced systemic oxidative stress. Our analyses revealed that systemic oxidative stress is related to lowered whole-body aerobic capacity and skeletal muscle dysfunction in CHF patients.

Clinical impact of admission urinary 8-hydroxydeoxyguanosine level for predicting cardiovascular mortality in patients with acute coronary syndrome

The aim of the present study was to determine whether urinary 8-hydroxydeoxyguanosine (8-OHdG), which is a marker of oxidative stress, can predict future cardiovascular death in patients with acute coronary syndrome (ACS). A total of 551 consecutive patients with ACS who underwent admission urinary 8-OHdG measurements were enrolled in this study. The patients were divided into 2 groups according to the optimal cutoff value of admission urinary 8-OHdG determined by a receiver-operating characteristics curve for the prediction of cardiovascular death: a high admission urinary 8-OHdG group, 169 patients with admission urinary 8-OHdG ≥ 17.92 ng/mg creatinine; and a low admission urinary 8-OHdG group, 382 patients with admission urinary 8-OHdG < 17.92 ng/mg creatinine. The patients were followed up for a median period of 34 months. The primary and secondary end points were the incidence of cardiovascular death and major cardiovascular events (MACE) composed of cardiovascular death, non-fatal myocardial infarction, or urgent hospitalization for heart failure. Of the 551 patients, cardiovascular deaths and MACE occurred in 14 (2.5%) and 35 (6.4%), respectively. The Kaplan-Meier estimate of the event-free rate revealed cardiovascular deaths and MACE were more likely in the high admission 8-OHdG group than in the low admission 8-OHdG group (log rank, both P < 0.001). Multiple adjusted Cox proportional hazards analysis indicated that high admission urinary 8-OHdG was an independent predictor of cardiovascular death (hazard ratio [HR] 7.642, P = 0.011) and MACE (HR 2.153, P = 0.049). High admission urinary 8-OHdG levels predict cardiovascular mortality after adjustment in patients with ACS.

Quantification of DNA Damage in Different Tissues in Rats with Heart Failure

Background

Chronic heart failure (CHF) is a complex syndrome which comprises structural and functional alterations in the heart in maintaining the adequate blood demand to all tissues. Few investigations sought to evaluate oxidative DNA damage in CHF.

Objective

To quantify the DNA damage using the comet assay in left ventricle (LV), lungs, diaphragm, gastrocnemius and soleus in rats with CHF.

Methods

Twelve male Wistar rats (300 to 330 g) were selected for the study: Sham (n = 6) and CHF (n = 6). The animals underwent myocardial infarction by the ligation of the left coronary artery. After six weeks, the animals were euthanized. It was performed a cell suspension of the tissues. The comet assay was performed to evaluate single and double strand breaks in DNA. Significance level (p) considered < 0.05.

Results

The CHF group showed higher values of left ventricle end-diastolic pressure (LVEDP), pulmonary congestion, cardiac hypertrophy and lower values of maximal positive and negative derivatives of LV pressure, LV systolic pressure (p < 0.05). CHF group showed higher DNA damage (% tail DNA, tail moment and Olive tail moment) compared to Sham (p < 0.001). The tissue with the highest damage was the soleus, compared to LV and gastrocnemius in CHF group (p < 0.05).

Conclusion

Our results indicates that the CHF affects all tissues, both centrally and peripherically, being more affected in skeletal muscle (soleus) and is positively correlated with LV dysfunction.

Exercise-Induced Regulation of Redox Status in Cardiovascular Diseases: The Role of Exercise Training and Detraining

Although low levels of reactive oxygen species (ROS) are beneficial for the organism ensuring normal cell and vascular function, the overproduction of ROS and increased oxidative stress levels play a significant role in the onset and progression of cardiovascular diseases (CVDs). This paper aims at providing a thorough review of the available literature investigating the effects of acute and chronic exercise training and detraining on redox regulation, in the context of CVDs. An acute bout of either cardiovascular or resistance exercise training induces a transient oxidative stress and inflammatory response accompanied by reduced antioxidant capacity and enhanced oxidative damage. There is evidence showing that these responses to exercise are proportional to exercise intensity and inversely related to an individual’s physical conditioning status. However, when chronically performed, both types of exercise amplify the antioxidant defense mechanism, reduce oxidative stress and preserve redox status. On the other hand, detraining results in maladaptations within a time-frame that depends on the exercise training intensity and mode, as high-intensity training is superior to low-intensity and resistance training is superior to cardiovascular training in preserving exercise-induced adaptations during detraining periods. Collectively, these findings suggest that exercise training, either cardiovascular or resistance or even a combination of them, is a promising, safe and efficient tool in the prevention and treatment of CVDs.

Detection of Active Inflammation Status Around Ventricular Aneurysms in Patients With Cardiac Sarcoidosis

BACKGROUND

Little is known about the pattern of isotope accumulation in the heart on ¹⁸F-fluorodeoxyglucose (¹⁸F-FDG) positron emission tomography in patients with cardiac sarcoidosis (CS) complicated by ventricular aneurysm (VA).Methods and Results:We prospectively enrolled 82 consecutive patients with CS; 54 patients with active CS (presence of abnormal ¹⁸F-FDG accumulation in the heart) were subdivided into VA (n=17) and non-VA groups (n=37). Strong ¹⁸F-FDG accumulation surrounding the VA and its disappearance in the VA center was observed in all patients with VA, probably because of scar formation at the VA. Peak standardized uptake value was higher around the VA than in the VA center (5.1±2.1 vs. 2.2±0.6, P=0.0003) and the VA center had no ¹⁸F-FDG accumulation (VA center: 2.2±0.6 vs. control area: 2.1±0.6, P=0.37). On the other hand, in non-VA patients with LV wall thinning (n=28), ¹⁸F-FDG accumulation was significantly high, even in the area of LV wall thinning (LV wall thinning area: 3.1±0.8 vs. control area: 2.0±0.6, P=0.00002).

CONCLUSIONS

A pattern of strong ¹⁸F-FDG accumulation surrounding the VA and its disappearance in the VA center might be characteristic in patients with CS complicated by VA. Careful attention to FDG uptake would further elucidate CS pathophysiology and aid in the early treatment of VA.

Mitochondrial reactive oxygen species generation in blood cells is associated with disease severity and exercise intolerance in heart failure patients

Systemic oxidative stress plays a key role in the development of chronic heart failure (CHF). We tested the hypothesis that mitochondrial reactive oxygen species (ROS) generation in circulating peripheral blood mononuclear cells (PBMCs) contributes to CHF progression. A total of 31 patients who had a history of hospital admission due to worsening HF were enrolled and grouped as having either mild CHF defined as New York Heart Association (NYHA) functional class I-II or moderate-to-severe CHF defined as NYHA functional class III. ROS levels in PBMC mitochondria were significantly increased in CHF patients with NYHA functional class III compared to those with NYHA functional class I-II, accompanied by impaired mitochondrial respiratory capacity in PBMCs. ROS generation in PBMC mitochondria was positively correlated with urinary 8-hydroxydeoxyguanosine, a systemic oxidative stress marker, in CHF patients. Importantly, mitochondrial ROS generation in PBMCs was directly correlated with plasma levels of B-type natriuretic peptide, a biomarker for severity of HF, and inversely correlated with peak oxygen uptake, a parameter of exercise capacity, in CHF patients. The study showed that ROS generation in PBMC mitochondria was higher in patients with advanced CHF, and it was associated with disease severity and exercise intolerance in CHF patients.

Effects of haem oxygenase-1 expression on oxidative injury and biological behaviours of rat dermal fibroblasts

OBJECTIVE

This study investigated the effects of high haem oxygenase-1 (HO-1) expression on oxidative injury and the biological behaviours of rat dermal fibroblasts, under high glucose conditions.

METHOD

Rat dermal fibroblasts were cultured in normal glucose (1.0g/l), high glucose (4.5g/l) or haemin (5μm). A bilirubin kit, real-time polymerase chain reaction (RT-PCR) and Western blotting measured the protease activity, mRNA, and protein levels of HO-1, respectively. An enzyme-linked immunosorbent assay (ELISA) kit measured media levels of 8-hydroxydeoxyguanosine (8-OHdG), reactive oxygen species (ROS) and collagen (hydroxyproline) secretion. Cell proliferation was measured using flow cytometry. Cell apoptosis was measured using Hoechst 33258 staining and flow cytometry. The transwell method and scratch test evaluated cell migration.

RESULTS

HO-1 expression exhibited a time-dependent change that was lowest in the high glucose (HG) group at 96 hours compared with the normal glucose (NG) group. In the HG group, the 8-OHdG, ROS and cell apoptosis were increased, and collagen secretion, cell proliferation and cell migration (horizontal and vertical) were decreased compared with the NG group at 96 hours. Haemin treatment sustained high HO-1 expression for at least 96 hours, and the cells exhibited decreased 8-OHdG and ROS, increased collagen synthesis, improved proliferation and migration ability, and decreased apoptosis in the NG and haemin (NH) group/HG and haemin (HH) group compared with the NG/HG groups. These cells recovered from oxidative injury and biological behaviours dysfunction.

CONCLUSION

Haemin induces HO-1 expression in fibroblasts and it may influence the oxidative injury and biological behaviours of fibroblasts. These findings suggest that HO-1 may accelerate the healing of diabetic wounds via alleviation of oxidative injury and improvement of biological behaviours of fibroblasts.

Efficacy of the Reactive Oxygen Metabolite Test as a Predictor of Initial Heart Failure Hospitalization in Elderly Patients With Chronic Heart Failure

Background

The reactive oxygen metabolites (d-ROMs) test has recently been explored as a novel marker of oxidative stress in vivo and used in clinical settings. Conversely, data regarding the utility of the d-ROMs test as a predictor of patients with chronic heart failure (CHF) are limited. This prospective study aims to elucidate the efficacy of the d-ROMs test as a predictor of initial heart failure (HF) hospitalization in elderly patients with CHF.

Methods

A total of 428 elderly outpatients with CHF with no history of HF hospitalization (108 males, 320 females; mean age, 75 ± 7 years) were enrolled. Based on the median value of d-ROMs test levels (303 U.CARR), the patients were divided into the following two groups: group L (low d-ROMs test levels) and group H (high d-ROMs test levels). The utility of the d-ROMs test as a predictor of initial HF hospitalization was evaluated.

Results

During the 88.1-month follow-up period, 58 HF cases were hospitalized (group L, 17 cases; group H, 41 cases; P < 0.001, log-rank test). Multivariate Cox regression analyses revealed that group H exhibited a significantly higher risk for HF hospitalization than did group L (hazard ratio (HR), 2.35; 95% confidence interval (CI), 1.37 - 4.43; P < 0.01). Furthermore, the HR (vs. group L with low brain natriuretic peptide (BNP) levels (< 200 pg/mL), HR, 9.18; 95% CI, 4.78 - 22.94; P < 0.001) for the incidence of HF hospitalization increased in group H with high BNP levels (≥ 200 pg/mL).

Conclusions

The present study demonstrates that high d-ROMs test levels predict initial HF hospitalization in elderly patients with CHF. In addition, the predictive value for the incidence of HF hospitalization increases by using a combination of two biomarkers as d-ROMs test and BNP levels.

Role of Uremic Toxins for Kidney, Cardiovascular, and Bone Dysfunction

With decreasing kidney function, cardiovascular disease (CVD) and mineral bone disorders frequently emerge in patients with chronic kidney disease (CKD). For these patients, in addition to the traditional risk factors, non-traditional CKD-specific risk factors are also associated with such diseases and conditions. One of these non-traditional risk factors is the accumulation of uremic toxins (UTs). In addition, the accumulation of UTs further deteriorates kidney function. Recently, a huge number of UTs have been identified. Although many experimental and clinical studies have reported associations between UTs and the progression of CKD, CVD, and bone disease, these relationships are very complex and have not been fully elucidated. Among the UTs, indoxyl sulfate, asymmetric dimethylarginine, and p-cresylsulfate have been of particular focus, up until now. In this review, we summarize the pathophysiological influences of these UTs on the kidney, cardiovascular system, and bone, and discuss the clinical data regarding the harmful effects of these UTs on diseases and conditions.

Association between human exposure to heavy metals/metalloid and occurrences of respiratory diseases, lipid peroxidation and DNA damage in Kumasi, Ghana

Heavy metals and metalloids contamination in soils, water, food and livers of wild rats have been studied in Kumasi, Ghana and despite the estimated risks to residents, there is no epidemiological study to ascertain these projections. In addition, the World Health Organization and International Agency for Research on Cancer have reported an increase in respiratory diseases and cancers, in Ghana. The study's purpose was therefore to explore the potential associations between metal exposure and occurrences of respiratory diseases, lipid peroxidation and/or DNA damage to different age groups and sexes in Kumasi. Human urine was collected from the general population in urban and control sites in Kumasi and nine metals were measured in each sample. Results showed that although Zn was the most abundant total urinary As concentration was higher in 83% of samples compared to reference values. Urinary concentrations of metals, malondialdehyde (MDA) and 8-hydroxy-2-deoxy-guanosine (8-OHdG) were higher in urban sites compared to the control site. Based on the results obtained, there was no significant correlation between urinary metals and age. However, urinary Cd and MDA were highest in age groups 61-85 and 3-20 years, respectively. Significantly higher levels of urinary Co, As and Cd were detected in female participants. The study revealed that exposure to As was significantly associated with increased odds of asthma (odds ratio (OR) = 2.76; CI: 1.11-6.83) and tachycardia (OR = 3.93; CI: 1.01-15.4). Significant association was observed between urinary metals and MDA and 8-OHdG indicating possibility of lipid peroxidation and/or DNA damage in Kumasi residents.

Respiratory muscle training decreases diaphragm DNA damage in rats with heart failure

Respiratory muscle training (RMT) promotes beneficial effects on respiratory mechanics, heart and lung morphological changes, and hemodynamic variables in rats with heart failure (HF). However, the relation between RMT effects and diaphragm oxidative stress remains unclear. Therefore, the aim of this study was to evaluate the RMT effects on diaphragm DNA damage in HF rats. Wistar rats were allocated into 4 groups: sedentary sham (Sed-Sham, n = 8), trained sham (RMT-Sham, n = 8), sedentary HF (Sed-HF, n = 8), and trained HF (RMT-HF, n = 8). The animals underwent a RMT protocol (30 min/day, 5 days/week for 6 weeks), whereas sedentary animals did not exercise. Groups were compared by a two-way ANOVA and Tukey’s post hoc tests. In rats with HF, RMT promoted reduction in pulmonary congestion (p < 0.0001) and left ventricular end diastolic pressure (p < 0.0001). Moreover, RMT produced a decrease in the diaphragm DNA damage in HF rats. This was demonstrated through the reduction in the percentage of tail DNA (p < 0.0001), tail moment (p < 0.01), and Olive tail moment (p < 0.001). These findings showed that a 6-week RMT protocol in rats with HF promoted an improvement in hemodynamic function and reduces diaphragm DNA damage.

Potential application of the oxidative nucleic acid damage biomarkers in detection of diseases

Reactive oxygen species (ROS) are generated after exposure to harmful environmental factors and during normal cellular metabolic processes. The balance of the generating and scavenging of ROS plays a significant role in living cells. The accumulation of ROS will lead to oxidative damage to biomolecules including nucleic acid. Although many types of oxidative nucleic acid damage products have been identified, 8-oxo-7,8-dihydro-2’-deoxyguanosine (8-oxodG) and 8-oxo-7,8-dihydroguanosine (8-oxoG) has been commonly chosen as the biomarkers of oxidative damage to DNA and RNA, respectively. It has been demonstrated that oxidative damage to nucleic acid is an initiator in pathogenesis of numerous diseases. Thus, oxidative nucleic acid damage biomarkers have the potential to be utilized for detection of diseases. Herein, we reviewed the relationship of oxidative nucleic acid damage and development of various diseases including cancers (colorectal cancer, gastrointestinal cancer, breast cancer, lung cancer, epithelial ovarian carcinoma, esophageal squamous cell carcinoma), neurodegenerative disorders and chronic diseases (diabetes and its complications, cardiovascular diseases). The potential of oxidative nucleic acid damage biomarkers for detection of diseases and drug development were described. Moreover, the approaches for detection of these biomarkers were also summarized.

Oxidative stress and respiratory symptoms due to human exposure to polycyclic aromatic hydrocarbons (PAHs) in Kumasi, Ghana

Studies of polycyclic aromatic hydrocarbons (PAHs) and its metabolites in PM10, soils, rat livers and cattle urine in Kumasi, Ghana, revealed high concentrations and cancer potency. In addition, WHO and IARC have reported an increase in cancer incidence and respiratory diseases in Ghana. Human urine were therefore collected from urban and control sites to: assess the health effects associated with PAHs exposure using malondialdehyde (MDA) and 8-hydroxy-2-deoxyguanosine (8-OHdG); identify any association between OH-PAHs, MDA, 8-OHdG with age and sex; and determine the relationship between PAHs exposure and occurrence of respiratory diseases. From the results, urinary concentrations of the sum of OH-PAHs (∑OHPAHs) were significantly higher from urban sites compared to the control site. Geometric mean concentrations adjusted by specific gravity, GM_SG, indicated 2-OHNaphthalene (2-OHNap) (6.01 ± 4.21 ng/mL) as the most abundant OH-PAH, and exposure could be through the use of naphthalene-containing-mothballs in drinking water purification, insect repellent, freshener in clothes and/or "treatment of various ailments". The study revealed that exposure to naphthalene significantly increases the occurrence of persistent cough (OR = 2.68, CI: 1.43-5.05), persistent headache (OR = 1.82, CI: 1.02-3.26), tachycardia (OR = 3.36, CI: 1.39-8.10) and dyspnea (OR = 3.07, CI: 1.27-7.43) in Kumasi residents. Highest level of urinary 2-OHNap (224 ng/mL) was detected in a female, who reported symptoms of persistent cough, headache, tachycardia, nasal congestion and inflammation, all of which are symptoms of naphthalene exposure according to USEPA. The ∑OHPAHs, 2-OHNap, 2-3-OHFluorenes, and -OHPhenanthrenes showed a significantly positive correlation with MDA and 4-OHPhenanthrene with 8-OHdG, indicating possible lipid peroxidation/cell damage or degenerative disease in some participants. MDA and 8-OHdG were highest in age group 21-60. The present study showed a significant sex difference with higher levels of urinary OH-PAHs in females than males.

Poor acute outcome in congestive heart failure is associated with increases in the plasma static oxidation-reduction potentials (sORP) in men but not in women

OBJECTIVES

In congestive heart failure (CHF), men are younger, more likely to have reduced ejection fraction (HF-rEF), and to be diabetic compared to women. Despite this, sex differences in oxidative stress have yet to be explored in CHF.

METHODS

Data from 67 males and 63 females hospitalized for CHF were collected. Static oxidation-reduction potential (sORP), a relative indicator of oxidative stress, and capacity ORP (icORP), a relative indicator of antioxidant capacity, were measured from plasma samples. We examined whether sex modified the relationship between ORP and hospital discharge disposition (poor outcome: death, hospice), along with other demographics, medications, and diagnostic parameters.

RESULTS

Males with poor outcomes had higher sORP and icORP values than females (P < 0.05). For those with a good outcome, there were no differences between the sexes (P > 0.05). Males were younger and more likely to have HF-rEF and diabetes. Controlling for these variables did not account for the sex differences in ORP measures. Regardless of sex, higher creatinine was related to higher sORP and icORP, while lower magnesium and potassium were related to higher sORP and icORP, respectively.

DISCUSSION

Increases in sORP during CHF are partially affected by sex and acute outcomes, but are also related to variables without sexual biases.

8-Hydroxy-2-deoxyguanosine levels and heart failure: A systematic review and meta-analysis of the literature

BACKGROUND AND AIMS

The generation of reactive oxygen species (ROS) plays an important role in the etiology of several pathological conditions. High levels of 8-hydroxy-2-deoxyguanosine (8-OHdG), a biomarker of oxidative damage of DNA, have been found in patients with heart failure (HF). We performed a meta-analysis of the literature to investigate the association between 8-OHdG levels and HF.

METHODS AND RESULTS

A systematic search was performed in the PubMed, Web of Science, Scopus, EMBASE databases and studies evaluating 8-OHdG levels in HF patients and controls were included. Differences between cases and controls were expressed as standard mean difference (SMD) or mean difference (MD) with pertinent 95% confidence intervals (95%CI). Impact of clinical and demographic features on effect size was assessed by meta-regression. Six studies (446 HF patients and 140 controls) were included in the analysis. We found that HF patients showed higher 8-OHdG levels than controls (SMD:0.89, 95%CI: 0.68, 1.10). The difference was confirmed both in studies in which 8-OHdG levels were assessed in urine (MD:6.28 ng/mg creatinine, 95%CI: 4.01, 8.56) and in blood samples (MD:0.36 ng/ml, 95%CI: 0.04, 0.69). Interestingly, 8-OHdG levels progressively increased for increasing New York Heart Association (NYHA) class. Meta-regression models showed that none of clinical and demographic variables impacted on the difference in 8-OHdG levels among HF patients and controls.

CONCLUSIONS

8-OHdG levels are higher in HF patients HF than in controls, with a progressive increase for increasing NYHA class. However, larger prospective studies are needed to test 8-OHdG as a biomarker of HF severity and progression.

Novel Biomarkers of Heart Failure

Although substantial improvements have been made in majority of cardiac disorders, heart failure (HF) remains a major health problem, with both increasing incidence and prevalence over the past decades. For that reason, the number of potential biomarkers that could contribute to diagnosis and treatment of HF patients is, almost exponentially, increasing over the recent years. The biomarkers that are, at the moment, more or less ready for use in everyday clinical practice, reflect different pathophysiological processes present in HF. In this review, seven groups of biomarkers associated to myocardial stretch (mid-regional proatrial natriuretic peptide, MR-proANP), myocyte injury (high-sensitive troponins, hs-cTn; heart-type fatty acid-binding protein, H-FABP; glutathione transferase P1, GSTP1), matrix remodeling (galectin-3; soluble isoform of suppression of tumorigenicity 2, sST2), inflammation (growth differentiation factor-15, GDF-15), renal dysfunction (neutrophil gelatinase-associated lipocalin, NGAL; kidney injury molecule-1, KIM-1), neurohumoral activation (adrenomedullin, MR-proADM; copeptin), and oxidative stress (ceruloplasmin; myeloperoxidase, MPO; 8-hydroxy-2'-deoxyguanosine, 8-OHdG; thioredoxin 1, Trx1) in HF will be overviewed. It is important to note that clinical value of individual biomarkers within the single time points in both diagnosis and outcome prediction in HF is limited. Hence, the future of biomarker application in HF lies in the multimarker panel strategy, which would include specific combination of biomarkers that reflect different pathophysiological processes underlying HF.

Recombinant Atrial Natriuretic Peptide Prevents Aberrant Ca2+ Leakage through the Ryanodine Receptor by Suppressing Mitochondrial Reactive Oxygen Species Production Induced by Isoproterenol in Failing Cardiomyocytes

Catecholamines induce intracellular reactive oxygen species (ROS), thus enhancing diastolic Ca²⁺ leakage through the ryanodine receptor during heart failure (HF). However, little is known regarding the effect of atrial natriuretic peptide (ANP) on ROS generation and Ca²⁺ handling in failing cardiomyocytes. The aim of the present study was to clarify the mechanism by which an exogenous ANP exerts cardioprotective effects during HF. Cardiomyocytes were isolated from the left ventricles of a canine tachycardia-induced HF model and sham-operated vehicle controls. The degree of mitochondrial oxidized DNA was evaluated by double immunohistochemical (IHC) staining using an anti-VDAC antibody for the mitochondria and an anti-8-hydroxy-2′-deoxyguanosine antibody for oxidized DNA. The effect of ANP on ROS was investigated using 2,7-dichlorofluorescin diacetate, diastolic Ca²⁺ sparks assessed by confocal microscopy using Fluo 4-AM, and the survival rate of myocytes after 48 h. The double IHC study revealed that isoproterenol (ISO) markedly increased oxidized DNA in the mitochondria in HF and that the ISO-induced DNA damage was markedly inhibited by the co-presence of ANP. ROS production and Ca²⁺ spark frequency (CaSF) were increased in HF compared to normal controls, and were further increased in the presence of ISO. Notably, ANP significantly suppressed both ISO-induced ROS and CaSF without changing sarcoplasmic reticulum Ca²⁺ content in HF (p<0.01, respectively). The survival rate after 48 h in HF was significantly decreased in the presence of ISO compared with baseline (p<0.01), whereas it was significantly improved by the co-presence of ANP (p<0.01). Together, our results suggest that ANP strongly suppresses ISO-induced mitochondrial ROS generation, which might correct aberrant diastolic Ca²⁺ sparks, eventually contributing to the improvement of cardiomyocyte survival in HF.

An oxidative stress biomarker, urinary 8-hydroxy-2'-deoxyguanosine, predicts cardiovascular-related death after steroid therapy for patients with active cardiac sarcoidosis

BACKGROUND

We investigated whether urinary 8-hydroxy-2'-deoxyguanosine (U-8-OHdG), a marker of oxidative DNA damage, is a prognosticator of cardiovascular-related death in patients with cardiac sarcoidosis (CS).

METHODS AND RESULTS

In this prospective study, 30 consecutive patients were divided into the active CS (n=20) and non-active CS (n=10) groups, based on abnormal isotope accumulation in the heart on (18)F-fluorodeoxyglucose positron-emission tomography/computed tomography ((18)F-FDG PET/CT) imaging. Nineteen patients in the active CS group underwent corticosteroid therapy. Before corticosteroid therapy initiation, U-8-OHdG, brain natriuretic peptide (BNP), other biomarkers, and indices of cardiac function were measured. Patients were followed-up for a median of 48months. The primary endpoint was the incidence of cardiovascular-related death. During the follow-up period, in the corticosteroid-treated active CS group, 7 of 19 patients experienced cardiovascular-related death. By contrast, in the non-active CS group, 1 of 10 patients died from cardiovascular-related causes. Univariate and multivariate analyses showed that U-8-OHdG and BNP were independent predictors for cardiovascular-related death. The cut-off values for predicting cardiovascular death in corticosteroid-treated patients with active CS were 19.1ng/mg·Cr and 209pg/mL for U-8-OHdG and BNP, respectively. Patients with a U-8-OHdG concentration ≥19.1ng/mg·Cr or a BNP concentration ≥209pg/mL had a significantly higher cardiovascular-related death risk, but U-8-OHdG had better predictive value compared with BNP.

CONCLUSION

These findings suggested that U-8-OHdG was a powerful predictor of cardiovascular-related death in patients with CS, suggesting that active CS patients with elevated U-8-OHdG levels might be resistant to corticosteroid therapy.

Oxidative stress and inflammatory markers - the future of heart failure diagnostics?

Heart failure remains one of the most important problems in cardiology despite the progress in its treatment. A number of recent studies have demonstrated the relationship between the intensification of oxidative stress and chronic inflammation and the severity of left ventricular dysfunction, development of heart failure symptoms, and prediction of future cardiac events. Early detection of changes developing in the heart is key in improving the treatment's effectiveness. It appears that determining specific, sensitive biomarkers reflecting the complex pathophysiology of heart failure and using them to detect asymptomatic cardiac alterations may become a crucial screening tool, assisting in the identification of patients requiring further diagnostic examinations. This article presents an overview of the current knowledge of the role of oxidative stress and inflammation in heart failure; it also discusses the potential role of oxidative stress and inflammatory markers as prognostic factors in heart failure that may be used in screening tests.

Oxidative stress biomarkers in long-term participants in clean-up work after the Hebei Spirit oil spill

BACKGROUND

The oil tanker Hebei Spirit spilled 12,547kL of oil near the western coastline of Korea on December 7, 2007. We aimed to investigate the relationship between oil spill exposure and oxidative stress in residents living near the affected area.

METHODS

Study subjects were 671 residents who participated in a health examination between February and September 2009. As surrogates for oil spill exposure, we used the total duration of clean-up work and levels of urinary metabolites of polycyclic aromatic hydrocarbons (PAHs), 1-hydroxypyrene (1-OHP) and 2-naphthol (2-NAPH). Oxidative stress was measured using urinary levels of malondialdehyde (MDA) and 8-hydroxy-2'-deoxyguanosine (8-OHdG), indicators of lipid peroxidation and oxidative DNA damage, respectively.

RESULTS

Levels of oxidative stress biomarkers were significantly increased with longer involvement in clean-up work over one year after the Hebei Spirit oil spill (MDA, p-trend<0.0001; 8-OHdG, p-trend<0.0001). As more time elapsed since the last involvement in clean-up, the total duration of clean-up work participation and levels of PAH metabolites (1-OHP and 2-NAPH), as well as levels of the oxidative stress biomarkers (MDA and 8-OHdG) decreased further. The level of 1-OHP had a significant positive correlation with the total duration of clean-up work involvement, with a higher level found in those who participated in clean-up for >100 days. Increasing levels of 1-OHP were significantly associated with increased MDA and 8-OHdG after adjusting for covariates, while the strength of association weakened as time passed since the last participation in clean-up work. The significance of the association was maintained for up to 12 months after the last clean-up work.

CONCLUSIONS

The results suggested that oil exposure from prolonged clean-up activity likely induced oxidative stress in clean-up participants up to at least one year after the last exposure.

Urinary 8-hydroxy-2'-deoxyguanosine as a novel biomarker of inflammatory activity in patients with cardiac sarcoidosis

BACKGROUND

Inflammation and oxidative stress play a crucial role in the pathogenesis of cardiac sarcoidosis (SAR). We investigated whether urinary (U) 8-hydroxy-2'-deoxyguanosine (8-OHdG)--an oxidative DNA damage marker--was related to SAR inflammatory activity.

METHODS

U-8-OHdG levels were measured in 31 SAR patients, classified as active (n=17) or non-active (n=14) based on (18)F-fluorodeoxyglucose positron emission tomography-computed tomography ((18)F-FDG-PET/CT), 28 dilated cardiomyopathy (DCM) patients, and 30 controls. In active SAR patients, U-8-OHdG levels were reexamined and compared with (18)F-FDG-PET/CT results at 6 months after corticosteroid treatment to assess therapeutic response.

RESULTS

Immunohistochemical examination of left ventricle (LV) autopsy samples from SAR patients revealed positive 8-OHdG staining in cardiomyocyte nuclei from LV sections showing (18)F-FDG accumulation on PET/CT, while serum 8-OHdG levels were significantly higher in the coronary sinus than in the aortic root only in active SAR patients. U-8-OHdG levels in SAR patients were higher than those in controls, and significantly higher in active SAR patients than in non-active SAR and DCM patients. U-8-OHdG was a powerful predictor of active SAR in receiver operating characteristic curve analysis (AUC, 0.98; 95% CI, 0.94-1.02; optimal cutoff value, 13.1 ng/mg creatinine), with a sensitivity of 88.2% and a specificity of 92.9%. U-8-OHdG levels in responders significantly decreased at 6 months after corticosteroid treatment initiation, in proportion with the decrease in the focal cardiac uptake of (18)F-FDG.

CONCLUSIONS

U-8-OHdG is a potentially clinically useful biomarker for evaluating inflammatory activity and monitoring the effectiveness of corticosteroid therapy in SAR patients.

Relationship between post-cardiac arrest myocardial oxidative stress and myocardial dysfunction in the rat

Background

Reperfusion after resuscitation from cardiac arrest (CA) is an event that increases reactive oxygen species production leading to oxidative stress. More specifically, myocardial oxidative stress may play a role in the severity of post-CA myocardial dysfunction. This study investigated the relationship between myocardial oxidative stress and post-CA myocardial injury and dysfunction in a rat model of CA and cardiopulmonary resuscitation (CPR). Ventricular fibrillation was induced in 26 rats and was untreated for 6 min. CPR, including mechanical chest compression, ventilation, and epinephrine, was then initiated and continued for additional 6 min prior to defibrillations. Resuscitated animals were sacrificed at two h (n = 9), 4 h (n = 6) and 72 h (n = 8) following resuscitation, and plasma collected for assessment of: high sensitivity cardiac troponin T (hs-cTnT), as marker of myocardial injury; isoprostanes (IsoP), as marker of lipid peroxidation; and 8-hydroxyguanosine (8-OHG), as marker of DNA oxidative damage. Hearts were also harvested for measurement of tissue IsoP and 8-OHG. Myocardial function was assessed by echocardiography at the corresponding time points. Additional 8 rats were not subjected to CA and served as baseline controls.

Results

Compared to baseline, left ventricular ejection fraction (LVEF) was reduced at 2 and 4 h following resuscitation (p < 0.01), while it was similar at 72 h. Inversely, plasma hs-cTnT increased, compared to baseline, at 2 and 4 h post-CA (p < 0.01), and then recovered at 72 h. Similarly, plasma and myocardial tissue IsoP and 8-OHG levels increased at 2 and 4 h post-resuscitation (p < 0.01 vs. baseline), while returned to baseline 72 h later. Myocardial IsoP were directly related to hs-cTnT levels (r = 0.760, p < 0.01) and inversely related to LVEF (r = -0.770, p < 0.01). Myocardial 8-OHG were also directly related to hs-cTnT levels (r = 0.409, p < 0.05) and inversely related to LVEF (r = -0.548, p < 0.01).

Conclusions

The present study provides evidence that lipid peroxidation and DNA oxidative damage in myocardial tissue are closely related to myocardial injury and LV dysfunction during the initial hours following CA.

Experimental biomarkers in heart failure: an update

Over the past 5 years, researchers have examined the utility of many experimental heart failure biomarkers that are not yet widely adopted clinically, to complement the role of B-type natriuretic peptide and its precursor. Candidate biomarkers have been identified from several different pathophysiologic categories, including markers of inflammation, myocyte necrosis, renal dysfunction, neurohumoral activation, oxidative stress and raised intracardiac pressure. Indeed, some biomarkers provide prognostic information that is independent of information obtained from conventional clinical and biomarker assessment. Moreover, some biomarkers studied help to identify dominant pathology that may predict responsiveness to specific therapies. Preliminary data also suggest a potential role for the development of comprehensive biomarker profiling models, integrating biomarkers from several categories to refine risk assessment.

Oxidative stress, DNA damage and repair in heart failure patients after implantation of continuous flow left ventricular assist devices

OBJECTIVE

To study the status of oxidative stress and DNA damage repair in circulating blood leukocytes of heart failure patients supported by continuous flow left ventricular assist devices (LVADs).

MATERIALS AND METHODS

Ten HF patients implanted with LVAD as bridge to transplant or destination therapy were enrolled in the study and 10 age and sex matched volunteers were recruited as the study control. Reactive oxygen species (ROS) in blood leukocytes and superoxide dismutase (SOD) in erythrocytes were measured by flow cytometry/immunofluorescence microscopy and spectrophotometry, respectively. ELISA was used to measure oxidized low density lipoproteins (oxLDL) in plasma. Markers of DNA damage (γ-H2AX) and repairs (Mre11, DNA ligase IV, Ku70, and Ku80) were quantified in blood lymphocytes by immunocytochemistry.

RESULTS

Levels of ROS and oxLDL were significantly higher in HF patients with LVAD than baseline as well as the control group; moreover, SOD levels were decreased with increasing post-operative periods. All the changes indicated enhanced oxidative stress among LVAD recipients. Significantly higher γ-H2AX foci in lymphocytes confirmed DNA double strand breaks in LVAD recipients. γ-H2AX foci numbers in lymphocytes were positively correlated with the ROS and oxLDL and negatively with SOD levels (p<0.0001). Expressions of DNA ligase IV, Ku70 and Ku80 proteins were highest after one week and Mre11 protein after 3 months of LVAD transplantation; indicated abnormal DNA repair.

CONCLUSIONS

The study, for the first time shows that, continuous flow LVAD implanted HF patients not only exhibit elevated oxidative stress and DNA damage in blood leukocytes but also have abnormalities in DNA repair pathways.

Antagonizing effects of soybean isoflavones on β-amyloid peptide-induced oxidative damage in neuron mitochondria of rats

Soybean isoflavone (SIF) has been demonstrated to have neuroprotective effects induced by β-amyloid peptides (Aβ) through suppressing oxidative stress; however, the explicit mechanisms still remain uncovered. In the present study, 32 Wistar rats were randomly divided into four groups: an Aβ1-42-treated group, a SIF + Aβ1-42 group, a SIF-treated group and a control group. We measured the protein content of 8-hydroxydeoxyguanosine (8-OhdG) and mRNA expression of 8-oxoguanine DNA glycosylase (OGG1). The protein expression of OGG1, Bcl-xl, Bad, beta subunit of ATP synthase (ATPB) and pyruvate dehydrogenase (PDH) in brain was also measured. The results showed that the level of 8-OHdG in both SIF groups was significantly decreased compared to the Aβ1-42-treated group (p < 0.05), while the mRNA and protein expression of OGG1 in the SIF + Aβ1-42 groups were up-regulated compared with the Aβ1-42-treated groups (p < 0.05). The expression of Bcl-xl was up-regulated in the SIF-treated group compared with the Aβ1-42-treated groups (p < 0.05), while the expression of Bad was down-regulated in the two SIF-treated groups (p < 0.05). Aβ1-42 significantly down-regulated the expression of ATPase and PDH proteins compared with the control group (p < 0.05). SIF reversed the down-regulation effects on the mitochondrial energy metabolic enzymes induced by Aβ1-42 (p < 0.05) in the rats. These results suggest that SIF alleviate the oxidative stress in neurons and mitochondria of rat brains mediated by Aβ1-42, and these protective effects might be associated with the regulation of OGG1, Bad, Bcl-xl, ATPB and PDH.

Association between oxidative stress assessed by urinary 8-hydroxydeoxyguanosine and the cardiac function in hypertensive patients without overt heart disease

Although increased oxidative stress is known to be associated with worsened cardiac function in chronic heart failure, consensus is still lacking regarding the association between oxidative stress and cardiac function in hypertensive patients without overt heart disease. This study aimed to evaluate the association between oxidative stress assessed by urinary 8-hydroxydeoxyguanosine (8-OHdG) and cardiac function in hypertensive patients without overt heart disease. We enrolled a total of 80 hypertensive patients (70 ± 11 y) who had been taking antihypertensive medications for at least 1 year. Urinary 8-OHdG levels were measured by an immunochromatographic assay (ICR-001, Selista Inc., Tokyo, Japan). Echocardiography was performed to assess the left ventricular (LV) diastolic function by measuring early diastolic mitral annular velocity (e') and the ratio of early transmitral flow velocity (E) to e' (E/e'). Urinary 8-OHdG was correlated with E/e' (r = 0.346, P = .002), e' (r = -0.310, P = .005), and HbA1c (r = 0.276, P = .013). Multiple linear regression analysis revealed that only e' (β = -0.343, P = .004) was an independent determinant of urinary 8-OHdG. In conclusion, decreased e' is independently associated with elevated urinary 8-OHdG, a marker of oxidative stress, in hypertensive patients. Therefore, an elevated urinary 8-OHdG level may be useful in detecting subclinical LV diastolic dysfunction in hypertensive patients without overt heart disease.

Beta-Blockers and Oxidative Stress in Patients with Heart Failure

Oxidative stress has been implicated in the pathogenesis of heart failure. Reactive oxygen species (ROS) are produced in the failing myocardium, and ROS cause hypertrophy, apoptosis/cell death and intracellular Ca²⁺ overload in cardiac myocytes. ROS also cause damage to lipid cell membranes in the process of lipid peroxidation. In this process, several aldehydes, including 4-hydroxy-2-nonenal (HNE), are generated and the amount of HNE is increased in the human failing myocardium. HNE exacerbates the formation of ROS, especially H₂O₂ and ·OH, in cardiomyocytes and subsequently ROS cause intracellular Ca²⁺ overload. Treatment with beta-blockers such as metoprolol, carvedilol and bisoprolol reduces the levels of oxidative stress, together with amelioration of heart failure. This reduction could be caused by several possible mechanisms. First, the beta-blocking effect is important, because catecholamines such as isoproterenol and norepinephrine induce oxidative stress in the myocardium. Second, anti-ischemic effects and negative chronotropic effects are also important. Furthermore, direct antioxidative effects of carvedilol contribute to the reduction of oxidative stress. Carvedilol inhibited HNE-induced intracellular Ca²⁺ overload. Beta-blocker therapy is a useful antioxidative therapy in patients with heart failure.